GTLC1, as a light chain encoding gene, was validated by DU et al. through functional enrichment analysis, immune microenvironment analysis, and in vitro cellular assays, and found that PRC1, GGTLC1, and IRS1 may mediate breast cancer chemoresistance through drug efflux, cell cycle regulation, redox state regulation, and alteration of the immune microenvironment. Research and development of therapeutic strategies targeting GGTLC1 may provide new therapeutic options for breast cancer patients [76]. The gene discussed is IRS1; the disease is breast cancer.